Saints Row the Third- It's such a blast to play. Ridiculous story, similar to GTA4 in gameplay but more extreme in every way.Battlefield 3- Never played Arma II but I've seen BF3 and Arma II comparisons. A lot of people seem to jump back and forth between the two for different gameplay styles. I own it on both PC and Xbox and oddly prefer the Xbox version because there's less chance of hacking.Binding of Isaac- a bullet-hell type of game, but it's really fun and quick, and very cheap on Steam (here's some gameplay vid). The story is light and the game has a Legend of Zelda feel to it.